Experimental performance evaluation of closed loop mist/fog cooling system for photovoltaic module application

Thermal degradation of the PV system is one of the main factors influencing the overall performance, especially under hot climatic conditions. An experimental investigation of a novel mist/fog based water cooling system is carried out for PV modules in outdoor conditions of Sharjah, UAE. This study intends to design and evaluate the performance of mist based water cooling system subject to the PV module application under extreme hot weather conditions. The mist/fog is created through the metallic nozzles with an orifice of 0.4 mm and applied uniformly on the rear surface of the PV module. The micro droplets forming mist/fog strike on the hot surface of the PV module, and instantaneous evaporation causes cooling. A temperature curtailment of 24.17% for front and 33.23% for rear surfaces is achieved, in the case of non-insulated mist box. Consequently, enhancement of electrical power by 13.54% is observed. While, in the case of thermally insulated mist boxes, temperature reduction of 27.01% for front and 34.25% for rear surfaces are observed with a 16.66% gain in electrical power. Besides, the mist cooling has ensured the uniform distribution of surface temperature to avoid thermal stress and eventually hot spots. The IR thermography confirms the uniform surface temperature profile of the PV module. Experimental results confirm the effectiveness of the mist cooling system in maintaining the significantly low temperature of PV modules and hence improving the electrical power.